function employee(name, job, born)
{
    this.name = name;
    this.job = job;
    this.born = born;
}

var bill = new employee("Bill Gates", "Engineer", 1985);
employee.prototype.salary = 2000;

console.info("name" in bill);
console.info("age" in bill);

console.dir(bill);
for (var prop in bill) {
    console.info("bill[" + prop + "]=" + bill[prop]);
}

